#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 1024

void error_handling(char* message);


int main(int argc,char *argv[]){

	int serv_sock ,clnt_sock;
	char message[BUF_SIZE];
	int str_len, i;
	struct sockaddr_in serv_adr, clnt_adr;
	socklen_t clnt_adr_sz;

	if(argc!=2){
		printf("error\n");
		exit(1);
	}

	serv_sock=socket(PF_INET, SOCK_STREAM, 0);
	if(serv_sock == -1){
		error_handling("socket() error");
	}
	memset(&serv_adr,0,sizeof(serv_adr));
	serv_adr.sin_family=AF_INET;
	serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
	serv_adr.sin_port = htons(atoi(argv[1]));

	if(bind(serv_sock,(struct sockaddr*)&serv_adr,sizeof(serv_adr))==-1){
		error_handling("bind error");

	}
	if(listen(serv_sock,5)==-1){
		error_handling("listen error");

	}
	clnt_adr_sz = sizeof(clnt_adr);
	for(i=0; i < 5; i++){
		clnt_sock=accept(serv_sock,(struct sockaddr*)&clnt_adr,&clnt_adr_sz);
		if(clnt_sock==-1)
			error_handling("accept error");
		else
			printf("connected client %d\n", i+1);

		while ((str_len=read(clnt_sock,message, BUF_SIZE))!=0)
		{
			write(clnt_sock,message,str_len);
		}

		close(clnt_sock);
	}
	close(serv_sock);
	return 0;


}

void error_handling(char* message){
	fputs(message,stderr);
	fputc('\n',stderr);
	exit(1);
}
